FYI, cupsaddsmb, which is bundled with CUPS, requires W32X86 (upper-case) for 32 bit driver installation and x64 (lower-case) for 64 bit driver installation. I noticed this when trying to add 64 bit drivers and my distro created an upper-case X64 directory (adding a symbolic link as lower-case was a usable workaround). And although Windows is case insensitive it does, with NTFS, preserve case and Windows 7, for example, has an upper-case W32X86, and a lower case x64.